Grass Hay — Livestock Feed Analysis
Grass hay is the foundational forage for most livestock operations, made from various grass species including fescue, orchardgrass, brome, and native prairie grasses. With 8% crude protein and 52% TDN on a dry matter basis, grass hay meets the maintenance requirements of most mature ruminants and equines without supplementation. Quality varies significantly with maturity at harvest, with early-cut grass hay providing substantially higher protein and energy than late-cut, stemmy hay. Grass hay is the preferred forage for easy keepers such as donkeys, miniature horses, and idle adult horses because its moderate energy content reduces the risk of obesity. For livestock with higher nutritional demands, grass hay serves as the forage base with protein and energy supplements added as needed.
Which Animals Can Grass Hay Feed?
The table below shows how Grass Hay performs as a sole feed source for each of the 20 livestock species in our database. At 8% crude protein and 52% TDN, this feed meets the protein requirement for animals needing up to 8% CP and the energy requirement for animals needing up to 52% TDN. In practice, feeds are rarely used as the sole source; this analysis helps determine where grass hay fits in a mixed ration.
| Animal | Needs CP | Needs TDN | As-Fed/Day | CP Met? | TDN Met? | Monthly Cost |
|---|---|---|---|---|---|---|
| Beef Cow | 7% | 52% | 27.3 lbs | Yes | Yes | $61.36 |
| Dairy Cow | 16% | 70% | 55.7 lbs | No | No | $125.28 |
| Horse | 10% | 55% | 25.0 lbs | No | No | $56.25 |
| Meat Goat | 10% | 55% | 6.0 lbs | No | No | $13.42 |
| Dairy Goat | 14% | 65% | 6.8 lbs | No | No | $15.34 |
| Sheep | 10% | 55% | 6.0 lbs | No | No | $13.42 |
| Pig (Sow/Boar) | 14% | 75% | 13.6 lbs | No | No | $30.68 |
| Pig (Grower/Finisher) | 16% | 80% | 8.5 lbs | No | No | $19.18 |
| Chicken (Layer) | 16% | 70% | 0.2 lbs | No | No | $0.51 |
| Chicken (Broiler) | 20% | 78% | 0.3 lbs | No | No | $0.77 |
| Turkey | 22% | 75% | 1.0 lbs | No | No | $2.24 |
| Duck | 16% | 70% | 0.4 lbs | No | No | $0.81 |
| Rabbit | 16% | 65% | 0.3 lbs | No | No | $0.72 |
| Llama | 10% | 55% | 7.2 lbs | No | No | $16.11 |
| Alpaca | 10% | 55% | 3.1 lbs | No | No | $6.90 |
| Donkey | 8% | 50% | 8.5 lbs | Yes | Yes | $19.18 |
| Bison | 7% | 52% | 40.9 lbs | Yes | Yes | $92.05 |
| Elk | 12% | 60% | 22.7 lbs | No | No | $51.14 |
| White-tailed Deer | 12% | 60% | 5.7 lbs | No | No | $12.78 |
| Miniature Horse | 10% | 55% | 6.8 lbs | No | No | $15.34 |
Cost Comparison with Similar Feeds
Selecting the most cost-effective feed requires comparing both the as-fed price and the price per ton of dry matter. The table below compares Grass Hay with other feeds in the forage category and common reference feeds. The cost per ton of dry matter accounts for moisture content, providing a fair comparison between feeds with different moisture levels.
| Feed | DM % | CP % | TDN % | $/Ton | $/Ton DM |
|---|---|---|---|---|---|
| Grass Hay | 88% | 8% | 52% | $150 | $170 |
| Alfalfa Hay | 90% | 18% | 58% | $250 | $278 |
| Timothy Hay | 88% | 9% | 55% | $200 | $227 |
| Bermuda Grass Hay | 88% | 10% | 52% | $160 | $182 |
| Whole Corn | 88% | 9% | 88% | $220 | $250 |
| Pasture Grass (Fresh) | 25% | 12% | 62% | $0 | $0 |
| Alfalfa Hay Cubes | 90% | 17% | 56% | $300 | $333 |
Feeding Guidelines for Grass Hay
When incorporating grass hay into a livestock feeding program, consider the following nutritional characteristics. With a dry matter content of 88%, each pound of as-fed grass hay provides 0.88 lbs of actual dry matter. The crude protein content of 8% means that each pound of dry matter delivers 1.3 grams of crude protein. The TDN content of 52% indicates the proportion of the feed that is digestible and available for energy.
The cost of grass hay at $150 per ton translates to $0.075 per pound as-fed or $0.085 per pound of dry matter. When evaluating whether to use this feed, compare the cost per unit of the nutrient you are trying to supply. If you need protein, calculate the cost per pound of crude protein. If you need energy, calculate the cost per unit of TDN. The most economical feed choice depends on which nutrient is the limiting factor in your ration and the relative prices of available feeds in your local market.
Storage requirements vary by feed type and moisture content. Feeds with less than 15% moisture (most dry hays and grains) can be stored in open-sided barns or covered stacks for months to years without significant nutrient loss. Feeds with higher moisture content require either airtight storage (silage, haylage) or must be consumed within days of delivery (wet brewers grains, wet distillers grains). Proper storage prevents mold growth, mycotoxin contamination, and dry matter losses that can significantly increase the effective cost per unit of nutrition delivered to the animal.
Always introduce new feeds gradually over a period of 7-14 days, increasing the proportion of the new feed while decreasing the old feed by equal amounts each day. Sudden dietary changes disrupt the microbial population in the rumen (for ruminants) or the hindgut (for horses), potentially causing digestive disturbances ranging from mild loose stools to life-threatening acidosis or colic. This gradual transition is especially important when switching between forages and concentrates, or when introducing high-starch feeds like corn or barley to animals previously consuming an all-forage diet.
Other Feed Types
Compare nutritional profiles and costs for all livestock feeds in our database.